Isotropic plasmas also support imaginary collective modes, if there is a chiral imbalance [1]}.
Chiral systems are of interest in a wide variety of different situations in particle physics, nuclear physics, condensed matter physics, and cosmology.
One important example is the chiral magnetic effect (CME) which is the production of a parity violating current in a plasma, in the presence of a magnetic field and an asymmetry between left and right handed fermions [2]}.
A chirally asymmetric plasma can be described using a chiral chemical potential defined as \(\mu _5 \equiv (\mu _R-\mu _L)/2\) , where \(\mu _L\)  and \(\mu _R\) 
are the chemical potentials of the left and right handed fermions.
The CME is particularly interesting in the context of heavy-ion collisions because it has been argued that the quark gluon plasma that is produced in non-central collisions may contain regions where \(\mu _5\)  is locally finite [3]}, [4]}, [5]}, [6]}, [7]}.
Instabilities in chiral plasmas have also been studied in electroweak theory at large lepton chemical potential [8]} and in the context of the early universe at \(T\gg \mu _5\)  [9]}.
